Ultrafine particle emissions from waterpipes

Objectives: Ultrafine particle emissions from waterpipes and their impact on human health have not been extensively studied. The aim of this study was to characterise the inhalation pattern of waterpipe smokers, and (a) construct apparatus to simulate waterpipe smoking in the laboratory, and (b) characterise mainstream emissions from waterpipes under different smoking conditions. Methods: Real life waterpipe smoking patterns were first measured with a spirometer. The average smoking pattern was then mechanically simulated in apparatus. Total particle number concentrations were determined with a condensation particle counter (CPC) for particles between 0.02 mm and 1 mm (P-Trak UPC, Model 8525, TSI) and the particle size fraction was determined with a differential mobility analyser (DMA) for particles from 0.01 mm to 0.5 mm. This instrument was coupled with a laser particle spectrometer for particles between 0.35 mm and 10 mm (Wide Range Particle Spectrometer, Model 1000XP, MSC Corp). Carbon monoxide levels were determined with an electrochemical sensor (Q-Trak monitor, Model 8554, TSI). Results: The tidal volume of an average waterpipe breath of 5 seconds was found to be 1 (SD 0.47) litre. The intervals between breaths on average were 25.5 (SD 10.2) seconds. Particle number concentrations of ultrafine particles in mainstream smoke during waterpipe smoking ranged up to 706109 particles per litre. The median diameter of the particles in a full smoking set with charcoal, tobacco and water was 0.04 mm. Smoke from the heated tobacco contributed to particles in the size range between 0.01 mm and 0.2 mm. The glowing piece of charcoal only contributed to particles smaller than 0.05 mm. Conclusions: Waterpipe smoking emits large amounts of ultrafine particles. With regard to particle emissions, smoking waterpipes may carry similar health risks to smoking cigarettes.